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TCP recvmsg seq # bug 2: copied DC66DE15, seq DC4CE377, rcvnxt DC62DEE9, fl 40
WARNING: CPU: 0 PID: 6500 at net/ipv4/tcp.c:2703 tcp_recvmsg_locked+0x80e/0x3660 net/ipv4/tcp.c:2701
Modules linked in:
CPU: 0 UID: 0 PID: 6500 Comm: syz.0.16 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:tcp_recvmsg_locked+0x80e/0x3660 net/ipv4/tcp.c:2701
Code: 48 c1 e8 03 42 0f b6 04 28 84 c0 4c 8b 74 24 18 0f 85 35 01 00 00 8b 0f 48 c7 c7 e0 0f 9e 8c 44 8b 44 24 3c e8 e3 40 92 f7 90 <0f> 0b 90 90 e9 40 ff ff ff 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c 10
RSP: 0018:ffffc90003b5f240 EFLAGS: 00010246
RAX: badf3efb7c5e7b00 RBX: 0000000000000000 RCX: ffff88803000bc00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000002
RBP: ffffc90003b5f610 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffffbfff1bfa1ec R12: ffff888032761640
R13: dffffc0000000000 R14: ffff888031d2e6e8 R15: ffff888032761668
FS:  00007ff9dede56c0(0000) GS:ffff888125c18000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff9dede4f98 CR3: 0000000033010000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 receive_fallback_to_copy net/ipv4/tcp.c:1945 [inline]
 tcp_zerocopy_receive+0x800/0x21d0 net/ipv4/tcp.c:2177
 do_tcp_getsockopt+0x1dd0/0x2660 net/ipv4/tcp.c:4665
 tcp_getsockopt+0x83/0x130 net/ipv4/tcp.c:4764
 do_sock_getsockopt+0x36f/0x450 net/socket.c:2405
 __sys_getsockopt net/socket.c:2434 [inline]
 __do_sys_getsockopt net/socket.c:2441 [inline]
 __se_sys_getsockopt net/socket.c:2438 [inline]
 __x64_sys_getsockopt+0x1a5/0x250 net/socket.c:2438
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff9ddf85d29
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ff9dede5038 EFLAGS: 00000246 ORIG_RAX: 0000000000000037
RAX: ffffffffffffffda RBX: 00007ff9de176080 RCX: 00007ff9ddf85d29
RDX: 0000000000000023 RSI: 0000000000000006 RDI: 0000000000000005
RBP: 00007ff9de001a20 R08: 0000000020000380 R09: 0000000000000000
R10: 0000000020000340 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007ff9de176080 R15: 00007ffc94c44458
 </TASK>